Zinc Nutrition Related to Critical Deficiency and Toxicity Levels for Sorghum1
- K. Ohki2
Sorghum [Sorghum bicolor(L.) Moench] production has increased in the Southeastern United States as a second crop in many doublecropping systems. Guidelines are needed for Zn concentration in leaf blade tissue for the diagnosis and correction of Zn deficiency and toxicity problems. The Zn critical deficiency level (CDL) and critical toxicity level (CTL) are the minimum and maximum concentrations, respectively, associated with a 10% yield reduction from maximum yield due to Zn deficiency and toxicity. Sorghum was grown in nutrient solutions containing Zn concentrations ranging from 0.0 to 91.78 nmol L−1 in 14 increments in the greenhouse. Individual blades were sampled at 49 days growth and analyzed for Zn concentration by atomic absorption spectrometry. The Zn CDL values in blades were 10, 10, 9, 13, and 24 µg g−1 for blades 1 (top), 2, 3, 4, and 5 (bottom), respectively, as calculated from the exponential relationship of Zn concentration in blades and top dry weight. The Zn CTL values in blades were 64, 68, 80, 100, and 195 µg g−1 in blades 1, 2, 3, 4, and 5, respectively. For tissue sampling to diagnose Zn deficiency and toxicity, blade 1 is recommended. The Zn CDL and CTL are 10 and 64 µg g−1, respectively, sampled at growth stage 2 and near maximum vegetative growth harvested at this time is expected if the Zn concentrations are within the CDL and CTL.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .